River Rock Coverage Per Ton and Per Yard, by Depth
Your supplier quoted tons. You measured a bed in square feet. How much does a ton of river rock cover is the question that closes that gap, and the answer is 80 sq ft at the usual 3 inch depth. Change the depth and everything below changes with it.
That covers
- What one ton does
- 80 sq ft at 3". Halve the depth and it doubles. Double the depth and it halves. Nothing else on this panel moves the answer nearly as hard.
- Why the stone size matters here
- Coverage is worked out from weight, and 1"–3" (most common) runs 2,700 lb a yard. Lighter stone means more yards to the ton, so bigger rock actually covers slightly more ground per ton than small.
- How this is worked out
- 2,000 lb ÷ 2,700 lb = 0.74 yd³ × 27 = 20 cu ft ÷ (3" ÷ 12) = 80 sq ft
What is coverage?
The floor area a quantity of stone makes when you spread it flat at a chosen depth. One ton, 80 square feet, 3 inches thick.
It has to be worked out because coverage is not a property of the rock. It is a property of the rock and a decision you make. The same ton is 120 sq ft or 60 depending only on how thick you lay it, and nobody can tell you that number but you.
The mistake is reading a coverage figure off a supplier board without checking the depth it assumes. Yards quote generously, often at 2 inches, which is thinner than most beds want. Order to that figure and you finish with bare ground showing.
How much does a ton of river rock cover?
80 square feet, laid 3 inches thick, in the usual 1 to 3 inch grade. That is a patch roughly 9 ft square.
The arithmetic behind it is short. A ton of this stone is 0.74 cubic yards, which is 20 cubic feet. Spread 3 inches thick, meaning a quarter of a foot, that volume reaches 20 ÷ 0.25 = 80 sq ft.
So that is less ground than most people expect from a word like ton. How much less? A single parking space is about 160 sq ft, so one ton of river rock covers half of one at bed depth.
Scale it from there. A 300 sq ft border wants close to four tons, and a small front yard at 800 sq ft is ten. Those are delivery quantities, not something you collect.
Coverage chart by depth
Depth is the whole story. Every inch you add takes ground away from the same quantity, and the relationship is not gentle: double the depth and you halve the coverage exactly.
| Depth | One ton covers | One cubic yard covers | Suits |
|---|---|---|---|
| 1" | 240 sq ft | 324 sq ft | Too thin for river rock, fabric shows |
| 2" | 120 sq ft | 162 sq ft | Minimum that hides the soil |
| 3" | 80 sq ft | 108 sq ft | Most landscaping beds |
| 4" | 60 sq ft | 81 sq ft | Slopes, dry creek beds, French drains |
Read down the middle column and the halving is obvious. 120 sq ft at 2 inches, 60 at 4. The one inch row is in there for completeness, not as an option, because a single inch of stone is a scattering rather than a surface.
This is why depth has to be decided before anything is ordered. Choosing 4 inches over 3 on a 500 sq ft area moves you from 6.3 tons to 8.3, which is another delivery and another delivery fee.
And the arithmetic runs the same way in reverse. Measure your area, divide by the figure in the ton column for your depth, and you have the tonnage to ask for. No calculator needed once the chart is in front of you.
Coverage by rock size
Bigger stone covers slightly more per ton, which surprises people who expect the opposite. It is a weight effect rather than a shape one.
Large rock leaves more air between the pieces, so a yard of it weighs less. Less weight per yard means more yards to the ton, and more yards means more ground.
| Stone size | Weight per yard | Covers at 3" | Wants at least |
|---|---|---|---|
| 3/4"–1" (pea-size) | 2,800 lb | 75 sq ft | 2" |
| 1"–3" (most common) | 2,700 lb | 80 sq ft | 2" |
| 2" | 2,700 lb | 80 sq ft | 3" |
| 3"–5" | 2,500 lb | 85 sq ft | 4" |
The last column undoes the third one, though. Oversized stone covers 85 sq ft per ton at 3 inches, but it cannot be laid at 3 inches. It needs 4, where the same ton does 65.
So the apparent saving on big rock is not real. Compare grades at the depth each one actually needs and small stone comes out ahead on ground covered per ton, which is the reverse of what the middle column suggests.
How much does a yard cover?
108 sq ft at 3 inches, 162 at 2 and 81 at 4. A cubic yard always covers more than a ton, since it weighs 1.35 tons.
And yard figures are cleaner than ton figures. A cubic yard is 27 cubic feet whatever the stone is, so coverage per yard does not change with grade at all. Only depth moves it.
Coverage per ton does change with grade, because the weight does. So if you are comparing two suppliers who quote in different units, convert both to yards first and the comparison gets simpler.
Which unit you are given usually depends on what else the yard sells. Places handling soil and mulch think in yards. Stone-only suppliers weigh everything, so you will get tons.
Recommended depth for full coverage
Three inches for a planting bed, and that is the figure to plan around unless something specific pushes you off it.
So what does full coverage mean? A layer with no line of sight through it to the ground. Get that and weeds are starved of light. Miss it and you have paid for stone that still leaves you weeding.
Two inches works where the stone is decorative and sitting over fabric, and it buys you 40 extra sq ft a ton. Four is for drainage runs, dry creek beds and slopes, where stone gets moved by water and needs the depth to stay put.
The hard rule underneath all of it: your depth cannot be less than your stone is wide. Three inch rock at two inches deep is a physical impossibility, and the coverage figure you calculated for it never existed.
Calculate coverage for your area
The converter at the top runs the direction this page is about. Put in the tons or yards you have been quoted, set your depth, and it returns the square footage that buys.
It gives the answer as a square as well, in feet a side. That sounds like a gimmick and it is the most useful output on the panel, because square feet are hard to picture and a 9 by 9 patch is not.
It also checks your depth against the grade you picked and says so when the two do not work together. That is the error worth catching, since it invalidates the figure rather than just shifting it.
Add about 10% to whatever it tells you. Ground is never flat, edges take more than they should, and coming up half a ton short means paying a second delivery fee to finish a corner.
River rock coverage questions
How much does a ton of river rock cover?
Roughly 120 sq ft laid 2 inches thick, 80 at 3 inches and 60 at 4. One ton of 1 to 3 inch stone is 0.74 cubic yards, near enough 20 cubic feet. Divide that by your depth in feet and you have the answer for any depth.
How much will a ton of river rock cover?
At the standard 3 inch bed depth, 80 sq ft, which is a patch about 9 ft square. Going shallower stretches it and going deeper burns through it, so settle the depth first. Nothing else changes the figure by as much.
How much does 1 ton of river rock cover?
Between 60 and 120 sq ft, depending entirely on depth. 60 at 4 inches for drainage work, 80 at the usual 3 inches for a planting bed, 120 at 2 inches where it is decorative only.
How much does a yard of river rock cover?
108 sq ft at 3 inches, 162 at 2 and 81 at 4. A cubic yard covers more ground than a ton because it weighs 1.35 tons, so check which unit your supplier quoted before comparing.
Does rock size change coverage?
Slightly. Larger stone weighs less per yard, so a ton of it is more volume and covers a little more ground. At 3 inches, 3 to 5 inch rock does 85 sq ft against 80 for 1 to 3 inch. The catch is that big stone needs 4 inches, which wipes the gain out.
How do I calculate river rock coverage?
Divide 20 cubic feet by your depth in feet. At 3 inches that is 0.25 ft, so 20 ÷ 0.25 = 80 sq ft a ton. For cubic yards use 27 cubic feet instead of 20.